Severus' experiment
by AshEdelstein
Summary: Sherlock and John find themselves unable to solve the latest case, when they meet Severus and Harry, who have admitted to killing the man.  When a forgotten experiment of Severus' is thrown in the mix, what will happen?


**So I got this idea after asking 'Severus Snape is tied to his desk…" on Omegle for a while out of pure boredom last night. One of the wonderbar strangers said to imagine Sherlock and Severus together, and I couldn't get the image out of my head. Happy reading all you wonderbar yaoi fans.**

**For the sake of my story, Moldyshorts has found a way to get his mortal body back, and Harry and Severus have formed a sort of father- son relationship. It will take a little bit to get to the sex, and so for people who just want some PWP I shall label the smexyness.**

Sherlock had no idea how to explain this case. There was nothing he could go on, no hidden marks and no damage to internal organs. There was nothing to even begin to point him in the direction of the killer. The only thing strange they had found on the body was a stick, shaped into something like a child's play wand.

"So, how do you explain this one Sherlock?" John asked from the doorway of the small room. "You just said it yourself; there is nothing at all to go on here. All we can see is that the man was a bit to obsessed with his fantasy stories."

Sherlock looked puzzled; he had spoken his inner ranting out loud. Curious, he hadn't even realised he had done that one. It was the case, it was so intriguing, Sherlock had to see it through to the end, but it was also unbelievably irritating.

"He is more than obsessed, John. He clearly believes that he lives like a magician, have you seen his basement?" Sherlock stood from the body, walking around it carefully and signalling for John to follow him down into the basement.

Sherlock delicately opened the door, opening it to reveal a dark room. Sherlock flicked on a torch, since he could find no matches for the candles, and threw the light around the room. He had seen the room earlier, but it was still a strange sight, the stuff in the jars around the room were even stranger than the stuff Sherlock kept in the fridge at Baker Street.

Suddenly the candles were all ignited together, revealing a dark clad figure standing in the corner of the room, browsing the strange things with an interest. "Don't mind me; I am merely taking back what is mine. I will be gone shortly, and then you can both return to your pointless investigation." The dark man didn't even turn around, he simply continued as if the other two weren't in the room. "I would put that gun down. You won't kill me with your Muggle weapons, you will simply make me angry." The man finally turned to face them, his obsidian eyes boring holes into their soles, "John Watson, ask any of my students. I am not a force to be crossed."

"You are an educator then?" Sherlock didn't really seem disturbed by the man, which made John glance at him. The dark eyes turned to his own pale ones, and Sherlock could feel a strange sensation in his mind, like the other man was there. "I am, Sherlock Holmes, but not the type that you seem to think I am. I do not teach Chemistry, I teach Potions to my students, not that you could call them that."

"Since you somehow managed to find out our names, why don't you inform us of yours?" Sherlock said, gliding over to a stole and kicking it out, glancing down into the cauldron that sat on the desk, "You do know that you have trespassed onto a crime scene. There is a dead man upstairs, in case you didn't know."

"Severus Snape. As for the dead man," Severus glanced up at the roof for a second, "He is of none of my concern. I do have to say he deserved a lot more than what happened to him. He crossed the wrong person one to many times."

"Would that wrong person have been you Severus?" Sherlock studied Severus intently, hoping to get some reaction from the strange man.

"Hardly, if I had had the chance to kill him there wouldn't be enough of him to even try and figure out what killed him." Severus turned back to the shelves and took down another jar, studying it before shoving it back on the shelf in disgust. "You need not concern yourself either, Mr Holmes. The man upstairs was a plague to our world, and to yours. I will have to ask you to leave now, I have revealed quite enough and I should really get these back to my ally."

"You seem to think we are from different worlds, and you called my weapon a 'Muggle weapon' earlier." John finally joined the conversation, cautiously joining Sherlock by the desk. He looked into the cauldron, thinking he was going to find some sort of dead animal in it, or a head like one of Sherlock's experiments, but all he saw was a semi-transparent violet liquid.

"You insist on being a nuisance." Severus pulled out a stick from his pocket, twirling it through the air. John and Sherlock gave him a look that clearly said they thought he was insane, and were about to tell him that when a strange blue light came from the wand and formed a beautiful blue doe. "Inform Harry that I have a slight problem here, he will have to come and assist me in finishing up the cleaning. It seems the Muggles somehow heard something and have come to investigate."

The blue doe raced around the room, brushing past Sherlock and John before it ran out the door and was lost to their sight. Severus snorted in amusement at their expressions, "You are both doing wonderful impersonations of gold fish, but do shut your mouths before you catch flies or something worse."

John turned to Sherlock, "You did just see that as well, didn't you Sherlock?" Sherlock couldn't answer, he had seen the doe, but his logical mind was telling him that it was a trick of his mind. He glanced around the room, and his eyes landed on the cauldron in front of him, it was whatever was in that, it obviously had a smoke to it that would make him see things. "It is a trick John; don't let it get to you. Think logical, there are two of us and one of him, we must arrest him."

"Sorry sir, but your message made no…" Another voice filled the room, and John and Sherlock turned sharply to the door to see a small boy with black hair and green eyes. "Now the message makes sense. How in the world did we manage to get the world's only consulting detective onto out case?"

"Obviously you took too much pleasure in making Him beg, the Muggles heard him." Severus didn't seem disturbed by the child, "How do you know anything about him though, did your horrid Aunt and Uncle let you watch TV after all?"

"Hardly sir, they left the TV on while they went out, and there was a program about him on." The boy said, gliding over to Severus with the grace of a wild cat, "By the looks of it you've been messing with their heads. You do enjoy that don't you, Professor?"

"Wait, you brought one of your students here? I thought you sent a message to you _ally_." John looked incredulous, his gaze shifting between the boy and back to Severus. "This is just getting strange. Sherlock, we have to do something about this now before things get out of hands."

"Harry isn't my student any more. The infernal brat just loves to taunt me about my position." Severus swiped a jar from the boys hands while he spoke, "As for doing something, I am sorry to say since we have told you this much, you are going to have to come with us. We need to erase those memories of yours. Harry will you grab the doctor?"

"You have been in their minds. Didn't you know Professor, curiosity killed the cat."

"Then you should stay well away from any curious ideas Harry, wouldn't want something like that killing you before I could put you in a potion would we?"

Harry poked his tongue out at Severus before he turned towards John, who had pulled his gun out again. Before he had time to think the gun was in Harry's hands, the raven haired boy grinning in satisfaction. "Can I play before I erase his memories sir?"

"So long as I don't find out what your 'play' involves, I don't really care what you do." Severus said in a stern voice. John eyed them both wearily, wondering just what the boy was getting at. He remembered Severus saying that his ally had killed the man upstairs, and it didn't take a genius to put two-and-two together and work out that this small boy in front of him was a murderer.

"A murderer, no I didn't murder any one. I just put down a beast in human form." Harry said with a chilling smile that stilled John, "Now, shall we John? I do believe Severus wanted your memories erased." Harry didn't give John any chance to say no, he grabbed the doctor's arm and then was gone, leaving Sherlock to stare at the spot where his friend had just been.

"Well, your turn Mr Holmes. I shall have to return to my task some other time, this is clearly more important." Sherlock spun around, coming face-to-face with Severus. He hadn't even heard the other man move, but he had no time to contemplate that, as his own arm had been grabbed and a strange sensation pulled at his stomach.

He hit the floor hard, landing on his knees and groaning in pain. Severus stood over him, looking imposing and completely in control of the situation. That annoyed Sherlock; all he wanted to do was tie the strange man to something and put him in his place.

"Do have patience Mr Holmes, we have only just met." Severus said, though his tone was nowhere near as scolding as he would have liked. Severus scanned through his memory, trying to work out what would have brought upon these thoughts and almost smacked himself. The potion, it had been an aphrodisiac, and an experimental one at that. Severus had only just enough time to wonder what trouble Harry had gotten himself into when he felt himself pushed harshly back into something solid behind him.

**Smexness starts here**

"I have no idea what you did to me Severus, but you are going to stop this madness." Sherlock growled, pressing himself into the dark clad man. Severus groaned throatily, pressing himself back into the warm, solid body before him. "I didn't do anything intentionally. It was an experiment left over from the other night; I had forgotten it was an aphrodisiac. The experiment obviously worked, the drug was released into the air, and did not need to be ingested."

"You mean I've been drugged?" Sherlock had begun tugging at the long, black cloak that Severus wore. Severus grew impatient, and not for the first time wondered what his life would have been like without magic. His clothes disappeared, along with Sherlock's, while a rope appeared in his hands. Sherlock gazed down at the rope, raising an eyebrow before he turned his attention back to Severus. "We have honestly just met Severus. I don't…"

"Shut up right now Sherlock and fuck me. This potion will not wear off until we find release from someone else affected by it, and since Harry and John are currently occupied, we will have to make do with each other." Severus growled. He didn't give the ropes to Sherlock; instead he used some wandless magic and tied himself to the desk he was leaning against. Before he completely lost his mind to the drug he summoned a potion and pressed it into Sherlock's hands, "Use that, it's a lubricant."

Sherlock gave up struggling and pressed his fingers into the liquid jar. He pushed two of them into Severus, relishing in the groan of pain that slipped past Severus' lips. "I'm going to fuck you Severus. I'm going to fuck you so hard I leave and impression of you on this desk for all your students to see."

Severus groaned at that, thrusting his hips up to try and find some friction against his neglected erection. He growled out a curse when Sherlock harshly dug his unoccupied hand into his thigh, causing Sherlock to moan deeply. Sherlock couldn't wait long enough to stretch Severus anymore; he pulled his fingers out, getting a whimper of protest. He grinned wickedly, "Beg me to fuck you."

"I beg for no one." Severus said through gritted teeth. Sherlock had lightly teased his erection, ghosting his fingers over the sensitive flesh. He wouldn't give in that easily though, and so he stubbornly refused to the demand made by the consulting detective.

"As much as the drug is telling me to simply pound you into this desk, I really am patient enough to wait for you to beg for it." Sherlock lowered his head, his lips latching onto the right side of Severus' neck, moving slowly up. "I can wait all night; your little Harry may come looking for you though. I know John has very little patience."

"I will not beg, I refuse to lower myself to that level." Severus was surprised that he still had enough of his mind to think straight. He had been in that room a lot longer than the other three, but Harry, and even John now that he thought about it, seemed to have been the most affected. He stored that piece of information away for later. Sherlock could see the faraway look on the others face and knew that he had drawn into his mind, for Sherlock knew that look all too well.

"Don't you dare draw into your mind Severus. You will beg me." Sherlock tugged harshly on the other man's erection, causing a startled moan to slip from thin lips and obsidian eyes returned to focus on Sherlock. He was still stubborn, so Sherlock stood and began to walk away from the other.

Severus knew he could have gotten himself out of the situation, or even forced Sherlock to fuck him, but there was something tugging at the back of his mind telling him to just give in. When Sherlock went to leave his stubbornness finally broke, "Fuck me, please. Fuck me hard!"

Sherlock felt a grin tug at his lips when he heard the desperate plea. He turned to find the distraught man was arching into the air, trying to find a non-existent pressure for his aching erection. Sherlock sidled back up to him and leaned over Severus again. "You beg so desperately. I will have to give in won't I?"

Sherlock covered his own aching erection in the liquid Severus had provided him with. He gazed down at the strange man who had tied himself to a desk and begged to be fucked by a complete stranger. Sherlock still refused to admit that this man was actually some sort of magician, but he didn't really care.

"Not a magician, they are from children's stories. I am a wizard; if you believe that or not I don't care, just fuck me already." Severus ground out, thrusting his hips up so that his erection met the strong muscles of Sherlock's chest. Sherlock didn't even think about how Severus knew what he had been thinking, he just slid himself into the tight heat that Severus offered so willingly, drawing a long moan from both of their lips.

Sherlock set a rough pace, not that Severus really seemed to mind. Severus threw his head back and fought with the bonds that he had wrapped around his own wrists. He didn't have enough control of his magic to get himself out of the situation, even if he had wanted to.

Sherlock himself was trying to stave off his own orgasm, trying to think about things that would at least hold off his orgasm for a few moments. He thrust harder into Severus, hitting the other man's prostate almost dead on. With a loud groan Severus clenched around him more, making it even harder to hold off his orgasm. Sherlock looked down at the man beneath him. He wasn't by any means handsome, but he wasn't ugly either. Sherlock wondered what would happen after this, the two strange men had been talking about erasing their memories of the event.

"Don't worry…Harry probably feels the same…we won't erase your memories." Severus panted through gasps for air. Sherlock felt a weight lift then, and his thrusts picked up speed. He didn't have any rhythm set, his movements were sporadic and misjudged, but that didn't bother either man. Sherlock finally gave in, spilling his orgasm into the tight heat that Severus offered. Severus felt the other man lose control, and whined when the consulting detective pulled out and fell on top of him.

Sherlock sat up and looked down, noticing that Severus hadn't cum at all yet. He reached his hand between their bodies and lazily stroked the other man over the edge. Severus' eyes closed in bliss and his hands came free from their binds. He didn't move though; instead he lay where he was, with Sherlock pressed against him panting.

"As much as having your weight pressing me into this desk is comfortable, please do sit up and allow me to have a shower." Severus said, pushing half-heartedly at Sherlock's chest. Sherlock sat up with a grunt, pushing himself up off the desk, "Want some company?" He asked, glancing at the mess that was on his chest as well. Severus didn't give a verbal response, but he did signal for Sherlock to follow him into another room.

"You think that experiment of yours has worn off yet?" Sherlock asked while he followed Severus. He glanced around quickly and noted that the sitting room they were now in was a lot more comfortable than the dark classroom they had been in earlier. "It should have, the outcome was achieved so the potion should now leave the system. That is, if I didn't mess with that part of it by adding other ingredients." Severus sounded thoughtful, and Sherlock was beginning to feel weary of that tone. Severus had walked into another room; one that he presumed was the bathroom. "No, it should have worn off, or we would still be trying to fuck each other's brains out."

"Wonderful description of what just happened. So you actually made that stuff then. What for?" Sherlock seemed honestly curious, and Severus had to turn to make sure it was still the same person. "I had nothing better to do with my time while we waited for that maniac to arrive; Harry was by no means an entertaining person to have a discussion with. Not that I don't care for the boy. He just needs to learn how to hold a conversation that isn't about Quidditch or pranks."

Sherlock ignored the word Quidditch and followed Severus into the bathroom. There was a large sower in the right corner of the room, and he sighed gratefully when Severus allowed him to follow him into the shower. Severus flicked his wrist and the water began to beat down on the two sticky bodies. Severus could feel the other man behind him, could feel his breath on his neck.

"My turn." He whispered and turned around to face Sherlock. Sherlock looked shocked when he was pushed against the wall, and his neck was attacked with nips and licks from Severus' mouth. Severus didn't give him much time to comprehend what was happening, he had lifted Sherlock up and wrapped the long legs around his waist. Severus summoned the jar of lubricant that had been left on his desk and slicked his fingers in it.

"Do you ever bottom to the doctor, Sherlock?" Severus asked in a whisper. Sherlock gapped at him, he hadn't told Severus that he and John were in a relationship. He shook his head at the question though and tensed when he felt Severus press his fingers into his tight passage. "This will be fun then. I do have to say, my partner won't be to please when he finds out I allowed myself to be affected by my own aphrodisiac."

"Is Harry your partner?" Sherlock gasped, the two fingers were plunging into him at a rough pace. Severus chuckled, "No, Harry is my son. I do not condone incest, even if he is just adopted." Severus added a third finger, taking pity on the tensed man he had pinned to the wall, "My partner could very easily walk through that door any minute now, Mr Holmes. I wonder what he would do?"

Sherlock had no time to respond to that, his breath was taken from his lungs when Severus pulled out his fingers and swiftly replaced them with his erection. Severus groaned when Sherlock tensed at the sudden intrusion, and Sherlock's nails digging into his back. Severus coaxed Sherlock into relaxing enough to start an uneven rhythm, which soon turned into frantic thrusting again when Severus found Sherlock's prostate.

"I'm going to cum, Severus." Sherlock called before he spilled himself onto his newly cleaned chest and Severus' as well. Severus continued with his pace, until he too gave in and filled Sherlock. Sherlock groaned lightly when Severus pulled out, but didn't complain when he was placed on the ground again and a soft cloth wiped his chest.

**Sex over, if you didn't want to finish the rest of the story**

"I should probably find Harry and John, and get you both home. Like I said, my partner could come at any time." Severus whispered. He stepped out of the shower and flicked his wrist to stop the stream of water. Sherlock followed, wrapping a towel around his waist and following Severus back into the class room. Sherlock didn't notice that Severus had stopped until he had walked into the other man's back.

"I told you he would be fine John, Severus doesn't really follow through with any of his threats." Harry's soft voice carried to Sherlock, and he tensed when he looked over Severus' shoulder and saw John looking at him. "Well, we should get these two home. I think dad is going to be here soon, we haven't returned home yet."

Severus didn't say anything, he grabbed Sherlock's arm and apparated them back to Spinner's End. Sherlock noticed they weren't in the basement again, and sighed softly at that fact. Severus chuckled, which made Sherlock look up in slight annoyance. "You have been reading my mind all night haven't you? You really are a wizard?"

"Yes, I told you that. Harry is too, and if I know him at all he has been messing with your friends mind as well." Severus said, just as Harry appeared with John clutching his arm. John looked between Sherlock and Harry, worry clear in his eyes. Sherlock strode over to John and took the other man in his arms, kissing him deeply.

"Let's go home John." Sherlock said. He turned to look at the two wizards standing away from him. "I will tell the police something about the murder, can I contact either of you if I find one like this again?"

"Most likely one of us will be there before you are. It won't always be wizards killed that way either, unfortunately Muggles get killed as well." Harry said, holding out his hand, "Until next time Mr Holmes?"

Sherlock took the offered hand, "Yes, until next time then, Harry, Severus." He then took John by the arm and lead them from the house. Harry and Severus watched them go before Harry turned to Severus, "That was your aphrodisiac experiment wasn't it?"

"Yes Harry, now let's get home, Remus must be worried." With that, the two apparated from the house.

**The part in the shower came to me this morning, after I fell asleep on my laptop last night writing the first part. **

**So I might write something about John and Harry's experience under the potion. The whole plot line kind of came out of thin air, and I hadn't even thought about John and Harry when they left, all I was focused on was getting the image of Severus tied to a desk with Sherlock over him into writing.**


End file.
